8 3/4 Rearends

[demondaddy]

Can Someone Enlighten Me On The Differences On 8 3/4 Cases.years,interchangability If Any,strenghts,weaknesses,advantages,disadvantages,spline Counts,availability Issues.also What Is A Cone Type Posi.as A Rock Crawler I Am Familiar With Spools And Lockers Of All Varities,and Understand Clutch Type Posis.any And All Info Is Appreciated.
Thank You!

 

[keith9291]

Heres a bunch of information...http://www.moparts.com/Tech/Archive/axle.html

 

[bobs340dartsport]

My understanding is:

Early cases are: 741 standard duty
742 heavy duty

later cases are: 489 heavy duty
The difference in the cases require different ring and pinion gear sets.
The difference is in the configuration of the pinion gear and crush sleeve.

All stock cases will interchange with all housings with stock axles.

stock axles have 30 splines, aftermarket axles can have 35 splines (but require a spool or posi unit with 35 splines)

Cone type posi units came in some (my car has one in it!), they work well but require cone and carrier replacement when they wear out.

Some posi units have 4 spider gears in them, I have one of those that works well also.

the other one I have is a clutch (EATON) type , it works well (like every sure grip I have ever had)

Bob